I understand that the shock wave from gunpowder moves at something under 5000 feet per second, meaning that this is the uper bound of velocity that can be attained in any gun using gunpowder as a propellant. I also understand that the shock wave from plastic explosive moves at a velocity numerous times that of gunpowder.

So, my question: Would it be possible to design a gun that uses plastique as its propellant, and in that way have a weapon that could shoot aimed projectiles at velocities of 10,000, or 20,000 or even more feet per second?

LE270,

The December 2001 issue of NRA's American Rifleman had a Q&A on a similar question. They report that about 30,000 fps is the max theoretical velocity attainable from smokeless power . Reality is lower.

The penetrating rod, discarding sabot rounds used in 120mm tank guns go out at over 4,000 fps. Art Alphin reported in the A-Square reloading manual that their work on the .416 Gerlach got about 5,300 fps. German and American military labs are working on light gas guns and rail guns -- getting into the directed energy realms as far as velocity goes. Not much application to rifles.

I recall that plastic explosives burn at about 27,000 fps; the problem with containing that burn rate in a physical thing is very tough. If you can solve this one, you probably could solve the fusion containment problem!

------------------
"if you are to busy to
hunt, you are too busy."

The explosive in C4 is RDX (I don't remember the long name). Back when I could get into the DOD research data base I downloaded a research paper that detailed the Army's experiments with RDX mixed with regular propellent to gain velocity in Tank Rounds. It was a success except for the fact that it made the rounds more dangerous to handle. They went back to the drawing board. May have solved that problem by now.
RDX (or C4) detonates which is different from burning. It decomposed in a shock wave that travels through the explosive. It traveles about 7800 meters per second through C4 (about the same as nitroglycerine) It generally can only be induced by a shock wave from a detonator. It would shatter a rifle. Also a lot of heat and gas is generated. RDX is plasticized into C4 to enable it to be molded around stuff to be cut. Like bridges. Also it makes it safer, and makes it slightly less powerfull.

I don't remember how they got around all this in the tank round. All explosives have a heat and pressure point where they will detonate. And they have a shock value that will cause them to detonate. There is research done to determine how far a 1KG weight has to be dropped on a sample to cause a detonation.

Todays top known explosives (CL 20, NIBT, nitrocubans) detonate at speeds up to 10 000m/s. If you want test something little bit slower, freeze your load with double base powder to -50C or lower and then fire it. You will see your rifle disintegrated !!
It will detonate, not burn . . . Detonation as bullet acceleration is unusable because very sharp pressure curve. If you are interested, I can compute aproximate pressure for example 500gr .458 bullet traveling 10000fps from 20" active barrel and you will se it is much over steel strength limits . . .

Possible - of course - guns for one use
Useful - For rifles etc. - NO

Apologize my English

Jiri

[This message has been edited by Jiri (edited 12-26-2001).]

Have you read the specifications of Remington's electronic gun? If I well remember, the propellant used is some type of plastic. The primer is ignited by an electrical pulse, much like a blasting cap.

......interesting theory

[This message has been edited by allen day (edited 12-26-2001).]

Electrically fired primers aren't new. The military has been using them for years. M61, M39 20mm guns are a good example of this.
To be classed as a low explosive, the reaction (deflagration or burning) happens at a rate of 400 m/s or less.
Low explosives don't have to be the only type of propellant used, but practicality dictates what has to be used. Guns that can contain the shock wave (and component integrity) can be built, but not in a small pkg that would be easily moved around.

As a point of interest, with std firearms primers, the composition is pored wet during manufacture.

Safe Shooting!
Steve Redgwell
303british.com

The basic problem with the idea is that plastique burns very, very hot. It is specifically designed to cut through steel. Since your rifle action is made of steel . . .

Sarge

"Plastique" is a term I have seen in books and in film but never encountered in my job among any manufacturers or users. It may be a WW2-era French underground name for the early moldable explosives (probably C-1, C-2 or C-3). Composition 4 or C-4 is composed mainly of hexogen (aka RDX) which is a nitramine compound formed on a benzene ring. It is very powerful, very brisant and reasonably insensitive compared with things like tetryl, NG and PETN. It is somewhat expensive. It has been the most widely used military explosive for half a century. If memory serves me WC870 is composed of about 60% RDX. It has definitely been used as a propellant, for which it is perfectly suited.

All smokeless propellants are modified high explosives. Jiri you must work for Semtex to know about CL-20 and nitrocubanes! We have looked at all of these for advanced propellants in the military sector, but they are probably prohibitively expensive for sporting applications. Also, as pointed out, you would need much stronger steels and heavier barrels to make use of those higher burning rates. I should emphasize here that any time you have a shock wave in the reaction front you have achieved detonation by definition. That is always a bad thing Rifle barrels would behave exactly like the casings on deep penetrating bombs under such conditions. To use the higher burning rates you would have to use higher pressures which also implies higher temperatures. All of these things put a lot of stress on the steel. I don't think it would be worthwhile to pay the high price for a 300M maraging steel barrel that could only fire 1000 rounds before it was eroded so badly that it was shot out. Those ultra-high velocities you see quoted come from sabot rounds in large smoothbore guns and multi-stage guns. None of that is practical for sporting use in any respect. It is very difficult to get the desired accuracy from those sabot projectiles in a smoothbore gun. Reducing the bore diameter will not improve the situation and you will be shooting needles at your target. Great for defeating armored deer with high explosive guts but not much use on real deer.

CL-20 is so unstable that I don't think the military will ever adopt it. We have had some very disturbing accidents already and only a handful of people are still willing to mess with it. ONC (octanitrocubane) the Holy Grail of high explosives was finally synthesized this past year, but its hideously expensive to produce and too impractical even for military use at present. Someday it may be possible for a more energetic propellant to improve the performance of small arms within the reasonable limits of metallurgy and cost, but I don't see that happening soon (although these "high energy" non-canister propellants are probably loaded with RDX).

I believe I have an article from the DOD data base that talks about ONC. Several years ago, as I have been retired since 1997. Is this the one that is supposed to have the Det velocity of 15,000 M/S?

Harald: I am only gun nut and chemistry is my hobby (was studing it for some time). Maybe there could be some improvents with change nitroglycerine with NIBT (nitroisobutylglyceroletrinitrate) or any other more powerfull and less volatile nitroester. I am not sure about triple base propelant usability for small callibers.

What do you think about NTO and it's salts ?

(apologize my english chemical terminology please )

Jiri, I am not a chemist and my knowledge is limited mainly to existing applications, plus what I have read in journals or other sources about new molecules (like ONC). I do have a little personal experience with CL-20, enough that I never again want to hold it in my hands. I couldn't make a very intelligent comment on the suitability of NTO as I am unfamilar with its characterstics. I do know that the Scandinavian powder companies (Norma and Vihta Vouri) have used triple base propellants loaded with nitroguanidine (NQ) and I suspect that RDX is in these newest "high energy" propellants like the 500 series VV powders and the non-canister grades loaded by Federal and others. Don't take that for gospel, its just a suspicion of mine. Did you know that the Czech Republic makes some of of the powders for Accurate?

Mike, the detonation velocity of ONC is expected to be in excess of 10,000 m/s. Pure HMX is around 9800 m/s and CL-20 is 9900+. The nice thing about ONC is that it will have a higher density (so you can pack more energy into the same volume) and that it is more stable than CL-20 and maybe more than HMX and RDX. Right now its just too expensive to do more than dream about. Its remarkably difficult to make - Nobel prize stuff almost.

Having used plastic explosives (C4), and having reloaded for over 30 years, I can only say this.

Sounds to me like a damn good way to blow your ass up for no good reason.

Regards,

Eric

------------------
Surely we must all hang together, for separately we will all surely hang.

I believe PETN, pentaerythritoltetranitrate (another plastic similiar in power to RDX) is used in naval gun propellant? Only a few percentage of the high explosive is added in the propellant.

Adding some high explosives to small arm propellant is possible, but it then become possible for buyers to extract high explosive from it, not very good for security. ("Bullseye" actually contain 40% of nitroglycerin. WHAT NOW? H335 with 3% C-4?)

High explosives produce pressure wave in millions PSI range, if load is toned down and both rifle action and barrel are titanium, the combination might stand a chance.

[This message has been edited by Pyrotek (edited 01-01-2002).]

For those of you that may not know, here's a general primer (if you'll pardon the pun).

Today's propellant explosives are typed or called "low explosives" because the reaction that happens to the composition travels at 400 m/s or less.
When dealing with SA propellants, there are 3 types - single, double and triple base propellants.
Single base - most commonly known are the IMR powders use nitrocellulose (NC) as their main ingredient.
Double base - a composition containing nitrocellulose (NC) and nitrogylcerin (NG). Adding NG produces higher velocities within acceptable pressure levels.
Triple base - contains NC, NG and NQ (nitroguanidine).
If you look on the side of your canisters, you will see that you have either single or double base.
In order to have higher velocities, there has to be a higher pressure created which usually means more heat and/or a quicker chemical reaction time. Early on, it was found that certain DB propellants subjected barrels to damaging heat. Today you will hear people speaking of using SB propellants to keep stress on equipment lower. For our pruposes, there's not a lot of truth in that today.
Because it's a propellant explosive, the reaction happens on the surface of the grains, and therefore does not travel through the composition as would a high explosive. The result therefore, is easier to control. When what we consider to be HE is added, it is blended together with NC using other compounds which influence burn time,ignition temp, sensitivity to ignition and to aid bonding. Also to resist separation.
As with any man made thing, Mother Nature does not like this artificial condition and she will attempt to pull them apart over time. A good example would be that car of yours rusting in the driveway.
The only danger in using what's normally classed as HE in the manufacturing process, is in the movement and blending of raw materials.
As far as having a propellant that would be considered a HE, where the reaction is 1,000m/s or faster AND using a device that is hand held, we're not there yet. The problem lies in containing the reaction in a device that is portable and cheap and easy to make. We'll be there one day. By then however, I suspect that copies of Rem 700s using "modern materials" will be like much of the reproduction stuff we buy today. Relegated to GI Action Shooting or 20 Century Reinactment groups. Personally, I can't wait!

Safe Shooting!
Steve Redgwell
303british.com

Harald: I know it. Company name is Synthesia, undersection Explosia, link is here : http://www.synthesia.cz/english/products/explosia.html, you can see different czech names for powders/accurate arms no . . .